Question

How would you prepare:

Calcium sulphate from calcium carbonate

Answer 1

1. Dissolve about 5 grams of Na₂CO₃ in 25 ml. of distilled water in a flask.
2. Keep this flask in a freezing mixture to cool it.
3. Pass CO₂ gas.
4. Crystals of sodium bicarbonate will precipitate and are dried after filtration.
5. Calcium sulphate can be prepared by reacting calcium carbonate with dilute sulphuric acid.

\[\ce{\underset{carbonate}{\underset{Calcium}{CaCO3}}+ H2SO4 -> \underset{sulphate}{\underset{Calcium}{CaSO4}}+ H2O + CO2}\]